Apparatus for the transfer of sensible and latent heat



Feb. 2, 1943. P. A. SCHERER APPARATUS FDR THE TRANSFER OF SENSIBLE AND LATENT HEAT 3 Sheets-Sheet 1 Filed Dec. 4, 1939 Feb, 2, 1943. 2,310,121

APPARATUS FOR THE TRANSFER OF SENSIBLE AND LATENT HEAT P. A. SCHERER Y Filed Dec. 4, 1959 5 Sheets-Sheet 2 Wm WM M6 4 1 d 'v I/ Feb. 2,

1943. P. A. SCHERER 2,310,121

APPARATUS FOR THE TRANSFER OF SENSIBLE AND LATENT HEAT Filed Dec. 4, 1959 3 Sheets-Sheet 3 516 $50 63 g 1771 8/7/0/1 35 I 26 P 7? VII/I/I/II'II/I/IA nww Patented Feb. 2, 1943 APPARATUS ron THE TRANSFER or SENSIBLE AND'LATENT HEAT Paul A. Scherer, San Francisco, Calif.

Application December 4, 1939, Serial No. 307,478

14 Claims.

This invention relates to heat transferring apparatus and relates more particularly to apparatus of this nature adapted for the treatment or conditioning of air, for use in fractional distillation, etc. A general object of the invention is to provide a practical, dependable, and particularly effective apparatus of this character.

Another object of this invention is to provide a multi-stage heat transferring apparatus suitable for use as an air conditioner in which there is effective latent and sensible heat transference in each stage.

Another object of this invention is to provide an apparatus of the character mentioned in which a cooling action and a drying action or dehumidifying action is carried on in two or more like or identical correspondingly positioned units, promoting economical manufacture and'installation.

Another object of this invention is to provide an apparatus of the character mentioned that is efiective in producing a marked reduction in-the temperature of the air treated while maintaim ing a low humidity.

Another object of this invention is to provide an apparatus of the character mentioned in which water and brine are employed as the evaporative and absorptive mediums and flow as films on the surfaces of spaced sheets of a materialv that is effective in the transference of the heat by conduction, and that is substantially unafiected by the liquids. In the improved apparatus of the present invention-glass sheets are utilized as the carriers for the liquid films and as heat conducting elements, the glass of the plates being effective in the conduction of the heat and being resistant to oxidation, corrosion, rot, etc.

Another object of this invention is to provide an apparatus of the character mentioned in whichthe plates are of unique shape or finish to assure the most efiective distribution of the liquid films over the plate surfaces.

Another object of this invention is to provide an apparatus of the character mentioned embodying novel and very effective regulable control means for controlling the thickness of'the liquid films on the plate surfaces to control or vary the action of the apparatus.

Another object of this invention isto provide an apparatus of the character mentioned in which the plate surfaces may be easily and quickly flushed from time to time as conditions may require, without dismantling the apparatus and without the removal of any of the parts.

vention will be fully understood from the follow:

ing detailed description of a typical, preferred form and application of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is an isometric perspective view of a pre. ferred form of apparatus of the invention. Fig. 1 is a schematic view illustrating the action of the apparatus. Fig. 2 is an enlarged side elevation of one unit or bank of the apparatus with portions broken away to illustrate certain elements in vertical cross section. Fig. 31s a vertical detailed sectional view taken as indicated by line 33 on Fig. 2. Fig. 4 is an enlarged fragmentary vertical detailed sectional view taken as indicated by line 4-4 on Fig. 3, and Figs. 5 and 6 are enlarged fragmentary horizontal detailed sectional views taken as indicated by lines 5-5 and 6-8, respectively, on Fig. 4.

The invention may be embodied in devices or apparatus varying considerably in purpose or application, for example, it may be embodied in air conditioning apparatus, in fractional distilling apparatus, in cooling towers, etc. In the follow-= ing disclosure 1 will describe the invention embodied in an air conditioning apparatus, it being understood that the invention is not to be considered as limited to this particular application or to the specific details herein described.

The apparatus of the present invention may be said to comprise, generally, two like units A and B each comprising abank of spaced sheets I!) and means ll supplying films of water and brine to the sides or surfaces of the sheets 10, means I! for circulating the air to be treated into contact with the films of the unit A, means [3 for circulating air between the water films of the unit A and the brine films of the unit B, and means I for circulating outside air into contact with the water films of the unit B.

The units A and B are preferably, though not necessarily, carried by a single or common base l5. The opposite sides iii of the base l5 have up- In the preferred construction the two units A,

and B are alike or identical to promote economy in the manufacture, and in the present disclosure corresponding parts of the units are designated by corresponding elements. The units A and B are supported on the base platforms I9 and are partially confined by the base side walls I6, I1 and I8. Each unit A and B includes a pan 22 resting on a platform I9. The pans 22 are engaged between the sides I6 of the base I5 and have lips 23 along their upper edges bearing on the flanged upper edges of the base sides I6. Longitudinally spaced gaskets 24 are arranged transversely under the pans 22 to seal with the platforms l9 and the base sides I6 to prevent the leakage of fluid under the pans. A gasket pad 25 of rubber, or the like, rests within each pan 22.

The plates or sheets II) are characterizing elements of the units A and B. The sheets I are preferably formed of glass or the equivalent, and are preferably alike or identical. Each unit A and B includes a series or bank of spaced substantially parallel sheets III. The sheets III of each unit are equally spaced apart and the units A and B have an equal number of sheets. The sheets III are arranged vertically, that is, the broad surfaces 26 of the sheets III are substantially vertical and the sheets have their lower edges resting on the gasket pads 26. The sheets It are positioned so that their broad surfaces 26 are in vertical planes substantially parallel with the planes of the base sides I6. In the preferred construction the sheets III are rectangular and are proportioned to project upwardly from the base I to have their upper edges adjacent the upper edges of the walls I1 and I8. The outermost sheets I0 engage against or lie adjacent the sides of the pans 22 while the opposite ends of the sheets III are at the ends of the pans. The pads 25 form supports for the sheets I0 and the weight of the sheets is such that the lower edges of the sheets are slightly embedded in the resilient pads 25 and dependable seals are formed at the pad, The engagement of the lower edges of the sheets ID with the pad 25 assists in holding the sheets in spaced parallel relation.

Drain plates 26 are arranged at opposite ends of the pans 22 to form the end walls of the pans. Gaskets 21 of rubber, or the like, are provided on the inner sides of the plates 26 to seal with the vertical end edges of the sheets [0. Tie rods 28- extend through the spaces between certain sheets I0 and pass through horizontal openings in the plates 26 and gaskets 21. The rods 26 carry heads or nuts 29 which clamp against the outer sides of the plates 26 to hold the gaskets 21 in tight sealing engagement with the end edges of the sheets Ill. The gaskets 21 may seal with. the opposite ends of the pans 22 to prevent leakage between the pans and the plates 26.

Means are provided to stabilize and hold the banks of sheets II! of the units A and B. These means include angle irons 30 gasketed to and extending upwardly from the sides I6 of the pans 22 and connected at their upper ends by horizontal bars or angle irons 3 I. The angle irons 30 and 3| occur at the outer sides of the outermost sheets I0. The angle irons 3| carry upwardly projecting lugs 32 and tie rods 33 connect the lugs 32 at the opposite sides of the sheet banks. The tie rods 33 preferably carry spacers 34 which extend horizontally across the upper edges of the spaced sheets I0. Plates 35 are arranged at the ends of the banks of sheets I0 adjacent the upper ends of the banks and gaskets 36 of rubber, or the like, are provided on the inner sides of the plates 35 to cooperate with and seal against the end edges of the sheets 10. Tie rods 31 are arranged horizontally in the spacesibetween certain of the sheets I0 and pass through openings in the plates 35 and gaskets 36. Nuts 38 are screwed on the ends of the rods 31 and clamp against the outer sides of the plates 35 so that the gaskets 36 are clamped against the edges of the sheets It to seal with the sheets and to assist in stabilizing the sheets. The plates 35 are adjacent the inner edges of the base walls I8.

In accordance with the invention the vertical surfaces 26 of the glass sheets I I) are finished or formed to insure substantially equal distribution of the liquid films. The surfaces 26 are corrugated, being provided with multiplicities of spaced parallel grooves 39. The grooves 39 extend vertically between the upper and lower edges of the sheets I0 and are provided throughout the entire sheet surfaces 26. The grooves 39 preferably have curved walls and are shallow. It is preferred to make the grooves 39 about .015 of an inch deep. The grooves 39 are equally spaced apart and are spaced and formed so that the surfaces 26 have alternate vertical ridges and grooves and, therefore, are, in effect, corrugated. The grooves 39 eliminate the tendency of the liquid to crawl or form lateral streams but are so shallow that the liquid is obliged to spread and cover the entire surfaces 26. The grooves 39 also perform a useful function in cooperation with certain elements of the means II, as will be later described. Further, the cooperation of the grooved surfaces 26 with the gaskets, etc. assures better sealing engagements and assists in stabi lizing the banks of sheets.

The means II for supp ying the films of water and brine to the surfaces 26 of the sheets III is a feature of the invention. The means II of each bank or unit A and B includes feed trays 40 and 40" arranged at the opposite ends of the bank of sheets III. The trays 40 and 40" are positioned at the above-mentioned plates 35 so that the plates form their inner walls. The inner edges of the trays 40 and 40' seal with gaskets ll on the outer sides of the plates 35. Securing rods 62 clamp the trays inwardly so that their inner edges tightly seal with the gaskets 4 I. The rods 42 may be associated with the tie rods 31. The upper edges of the trays 40 and 40' may be .substantially flush with the upper edges of the walls I1 and I8. The ends of the trays 40 and 46'' may cooperate with the inner surfaces of the walls I1 and I8. The trays 46 carry brine or other suitable liquid having a lower vapor pressure than water while the trays 46" carry water. It is to be noted that where the units A and B are arranged in end to end relation and in corresponding positions, the tray 40 of the unit A is adjacent and in opposing relation to the tray 40 of the unit B. The trays 40 and 40" are sup-" plied with liquid from the sumps 20. Liquid lines or pipes 43 extend from the sumps 20 to the related trays 4|! and 40". Motor driven pump units 44 are connected in the pipe 43 to pump the liquid from the sumps to the trays.

The trays4il and 40" serve to deliver thebrine and water to the spaces between the spaced sheets 10. Ports 45 are formed in the plates 35 and the gaskets 36 to connect the interiors of the trays 40 and 40 with the spaces between the plates 10. The ports 45 are horizontally spaced so that a given tray 4t or 40" communicates with every other space defined by the spaced plates 16. Thus the ports 45 place the sumps 46 in communication with the spaces 46' andplace the trays 40 in communication with the spaces 46'. The spaces 46? and 46 are intermeshing, that is, each bank of sheets III has or defines a space 46, a space 46, a space 46, and so on.

The liquid supplying or handling means ll further include control elements or valve elements governing the delivery of the brine and water to the major portions of the sheet surfaces 26 to cover the surfaces with liquid films. The valve elements are in the nature of tubes 41 of rubber or other flexible resilient material arranged horizontally in the several spaces 46 and 46 but below the ports 45. The end portions of the tubes 41 pass through openings 46 in the plates 35 to project outwardly from the plates.

tubes 41 to internal pressure so that they are expanded into sealing engagement with the surfaces 26 to control the escape or flow of the liquid from the portions of the spaces 46 and 46"above the tubes. One manifold 49 of each unit A and B has a valved connection 54 for admitting fluid under pressure. The fluid under pressure supplied to the manifolds 49 and the tubes 41 expands the tubes to engage and seal against the surfaces 25. By varying the pressure of the fluid admitted to the manifolds 49 the tubes 41 are expanded to a greater or less extent to control the rate of liquid flow down the surfaces 26 of the sheets Hi. It is to be noted that all of the valve tubes 41 of a unit A or B are simultaneously expanded or deflated to the same degree by admitting or exhausting the fluid pressure at the fitting 54. The tubes 41 seal against the surfaces 26 to oblige the liquid to run down the grooves 38. The exteriors of the expanded tubes "engage the ridges occurring between the grooves 36 and being flexible and formable may partially close the grooves 59. The tubes 41 seal with or engage thesurfaces 26 deflning the Headers or manifolds 46 bear against the gaskets 4| of the plates 35 to have their interiors in communication with the tubes 41. Bushings or ferrules 50 are arranged in the portions of the tubes 41 which pass through the openings 48. The external diameter of the ferrules 56 is substantially equal to the normal internal diameter of the tubes 41. The tubes 41 are sealed and secured in the openings 48 in a novel, improved manner. Following the insertion of the ferrule 50 in an end portion of a tube 41 this portion of the tube is put under tension and is stretched or elongated. This elongation is accompanied by reduction in the wall thickness of the tube 41 and the portion of the tube thus reduced in external diameter is passed through an opening 48. The tension is then removed from the tube 41 and the tube expands through its resiliency to have tight sealing cooperation with the wall of the opening 48. The ferrules 50 are formed of rigid material and form internal supports which prevent a reduction in the internal diameter of the tubes when the tubes are set in the openings 46, as described.

The manifolds 49 are held in place by tie rods 5| provided with nuts 52 that clamp the manifolds against the gaskets 4|. The tie rods 5! pass through certain of the tubes 41. The other tubes 41 contain rigid rods 53. The rods 5! and 53 are considerably smaller in diameter than the tubes 41 to leave clear annular passages in the tubes. The rods 5! and 53 serve to prevent distortion and sagging of the'tubes 41. The liquid from the trays 40 and 46" is admitted to the spaces 46 and 46' above the tubes 41 and the upper portions of the spaces may contain substantial quantities of the liquid. The rods 51 and 53 serve to support the flexible tubes 41 so that the weight of this liquid does not excessively distort the tubes.

The tubes 41 constitute sealing elements or valve elements for sealing with the surfaces 26 of the sheets. There is a tube 41 provided in each space 46 and 46' and the tubes 41 are proportioned so that they normally or initially clear the surfaces 26 or engage but. slightly against the surfaces. The invention provides means for inflating. the tubes 41 or for subjecting the spaces 46 and 46' and control the escape or discharge of the brine and water in such a manner that films of the brine and water flow down each surface. It will be observed that the surof brine on one surface 26 and a film of water" on its other surface 26.

The films of brine and water flowing down the surfaces 26 ofthe sheets iii are, of course, stopped by the gasket pads 25 in the pans 22. The liquid flows along the pads 25 to the plates 26, or accumulates in the pans 22. Discharge openings 56 are provided in the plates 26 and their gaskets 21 to communicate with the lower ends of the spaces 48 and 45". The ports 56 are in the same relation as the ports 45 and serve to discharge the liquids from the lower ends of the spaces 46 and 46' to the sumps 20 for recirculation to the trays 46 and 40" by the pump means 44.

The means l2 operates to circulate the air to be treated through the spaces 46' of the unit A to be cooled, dried, and de-odorized through contact with the brine films flowing down the surfaces 26 defining said spaces. The means I2 includes a suitable air conduit 51 extending from the compartment or space being conditioned. The conduit 51 has its outer end in communication with the outer end of the unit A. The outer end of the air conduit 51 Joins or is received between the walls l8 and is between the tray 40* and the end sump 26 of the unit A. A longitudinal horizontal partition 58 extends longitudinally through the conduit 51 to divide the conduit into upper and lower passages. Sets of suitable louvers 59 are provided at the outer ends of these passages where they communicate with the space being conditioned. The partition 58 extends to or joins a substantially horizontal shelf 60 arranged between the outer end walls 86 of the unit A. Partition rods 6| extend into the spaces 46'' of the unit A. The rods 6| extend inwardly from the shelf 60 and terminate in a vertical plane spaced some distance from the vertical plane occupied by the inner edges of the sheets I 6 of the unit A. The rods 61 may be supported onthe shelf 55. In accordance with the invention the rods 6| form horizontal barriers or air deflectors in the spaces 46 of the unit A.

The air handled by the conduit 5'! is prevented from entering the spaces 46" of the unit A and the air in the spaces 46 of the unit A is prevented from entering the spaces 46. In a simiunit B are closed. The means for closing the said ends of the spaces 46" and 46" comprise members 62 of wood or metal arranged against the edges of pairs of adjacent sheets ill. Inner members 63 of rigid material are inserted between the pairs of sheets In in spaced adjacent relation to the outer members 62 and vertically disposed tubes 64 of rubber, or the like, are arranged between the opposing members 62 and 63. The tubes 64 are initially cylindrical and formed to rather snugly fit between the opposing surfaces 26 of the sheets I0. Following the assembling of the tubes 64 between the members 62 and 63, the members 63 are moved outwardly toward their related members 62. Screws 65 passing through openings in the members 62 and threaded in openings in the members 63 may be employed to accomplish this movement. Movement of the members 63 toward the members 62 distorts the tubes 64 and this distortion causes the tubes 64 to tightly seal with the surfaces 26 of the-sheets ID to prevent the leakage ofliquid and air.

The means 12 for bringing the air to be treated into contact with the brine films of the unit A further includes air moving means. This air moving means may be in the nature ofa motor driven fan 66 arranged on the shelf 60. The fan 66 draws air in-through the lower passage of the conduit 51 and drives the treated air out through the upper passage of the conduit 51. The air is thus made to circulate through the spaces 46" of -the unit A and is brought into conunits A and B. The partition 66 may serve to support the rods. 61. Air moving means in the form of a motor driven fan 66 or its equivalent the unit B. Fig. lfllustrates the path of the tact with the brine films of these spaces throughout substantially the entire extents of the sheets l6. As will be later described, the brine films act as cooling, drying (condensing) and de-odorizing agents for the air and the sheets Ill serve to conduct heat from the brine films to the water films on their opposite surfaces. 7

means i8 operates to continuously circulate aj'streamof air through the spaces 46' of the unit A and the spaces 66' of the unit B. With the closure means 62-63-64 arranged as described above, the inner edges of the spaces 46' of the unit A are open and directly oppose the open inner ends of the spaces 46 of the unit B. The

means l3 includes partition rods 61 extending tween the units-A and B disposed in substantially the same plane as the rods 61. The partition 68 extends between the side walls I! of the base and the inner edges of the sheets 10 of the air circulated by the fan 69.

The means l6 handles outside air and brings this air into contact with the water films of the spaces 46" of the unit 13. The means It includes a suitable air conductor or conduit 10 leading,

to the atmosphere and having its inner end in communication with the spaces 46' of the unit B. The conduit III is connected with or received between the plates [6 of the unit B to communicate with the outer ends of the spaces 46' between the tray 40" and the related sump 20. A horizontal partition II extends longitudinally through the conduit 10 to divide the conduit into upper and lower passages. Partition rods 12 extend into the spaces 46' of the unit B and terminate in a vertical plane spaced from the inner edges of the sheets Ill. The rods 12 may lie in the same plane as the partition H. A shelf 13 forming an inner extension or the partition H supports the rods I2. A motor driven fan 14 or its equivalent is supported on the shelf 13 to circulate the air through the spaces 46" and the conduit I0. Fig. 1 of the drawings illustrates the manner in which the fan I4 circulates the air.

In the operation of the apparatus the fans 66, 69 and 14 are in continuous operation and sufficient supplies of water and brine are maintained in the trays 40 and 40" to assure the formation of the brine and liquid films on the surfaces 26 of the plates [0. I prefer to employ a brine solution of calcium chloride, although the "brine" used in the apparatus may be any suitable liquid having a lower vapor pressure than water. It is preferred to maintain the concentration of the brine or solution substantially constant for the eificient operation of the apparatus. As described above, the fan 66 delivers the air to be treated to the unit A and handles it in such a manner that it is made to come into contact with the brine films in the spaces 46" of the unit A, the fan 69 continuously recirculates a stream of air in such a manner that it passes through the spaces 46" of the unit A and the spaces 46" of the unit B and the fan 16 circulates the outside lair through the spaces 66' of the unit B. The action resulting from this circulation of air into contact with the brine and water films is as follows: The outside air brought into contact with the water films in the spaces 46" of the unit B results in evaporative cooling, causing the temperature of these water films to approach the wet bulb temperature of the atmosphere. Byheat conduction through the plates ll of the unit B the brine films flowing down the surfaces 26 of the spaces 46 of the unit B also approach the atmospheric wet bulb temperature. The brine filmsei t txmt. to 21 58 l d in the art h 'sp ib P3 55 1 f ,v I ID or the units. "The in the,spaces.4,

e we: am? p el e m the named sheet tdproVid' "for ionization ofithe ah.

B m" thii pa e there is a substantial reduction the liquid flow down the surfaceg gptfth she'et --:i d -i:.=-T fiamwl wqgifl nd m d ti peratiom nd requires am n li mfit r erv in i zle. 1141 m pressure in the; 1 4 .654

he surface Z Q thQPE QS ,7 l wi th -tfl eh e t m e E1 $5 x -i t qthq selett dl e xt-.

Ha ingides rlbedq lyat nlq m iewe andt nli e w mihm ,1m? 1 vQ9 et to. be m itQ or rest qtetdfiq thwpfi herein set forth, but wish to reser y any'vari'ations or modifications that may abbear and means bringing the air to be treated into contact with the film of lower vapor pressure on said other sheet to give up heat and moisture, said surfaces of the sheets having grooves extending longitudinally of the direction of travel of the films.

6. Apparatus for the transfer of sensible and latent heat comprising at least two generally up right sheets of glass, means for feeding liquid to the opposite surfaces of the sheets to form downwardly flowing films on the surfaces, the liquid of one film of each sheet having a lower vapor pressure than the liquid of the other film, means for bringing air into contact with the film of higher vapor pressure on one of the sheets to bring about a reduction in the temperature of said film by an evaporative action, said sheet conducting heat from its film of lower vapor pressure to its film of higher vapor pressure, means for circulating a stream of air to move from the film of higher vapor pressure on the other sheet to the film of lower vapor pressure on the first named sheet and back to the film of higher vapor pressure on said other sheet to give on heat and moisture through contact with the film of lower vapor pressure on said first named sheet and to have an evaporative cooling action on the film of higher vapor pressure of said other sheet, said other sheet conducting heat from its film of lower vapor pressure to its cooled film of higher vapor pressure, and means for bringing the air to be treated into contact with the film of lower vapor pressure on said other sheet.

7. In apparatus for the transfer of sensible and latent heat two units, each unit comprising a series of horizontally spaced substantially vertical sheets, means for supplying liquid to the upper parts of alternate spaces between the sheets, means for supplying liquid of a lower vapor pressure to the upper parts of the other spaces between the sheets, and means for causing said liquids to run down the surfaces of the sheets in films, the spaces of one unit carrying the liquid of higher vapor pressure being in communication with the spaces of the other unit carrying the liquid of lower vapor pressure, means for circulating air through the said communicating spaces to move from the first named unit into the second named unit and then back into said first named unit, means for'moving outside air through the spaces of said other unit carrying the liquid of higher vapor. pressure, and means for moving the air to be treated through the spaces of the first named unit carrying the liquid of lower vapor pressure. a

8. In apparatus for the transfer of sensible and latent heat, two spaced sheets having opposing grooved surfaces, means for delivering liquid to the space between the sheets, and means for causing the liquid to flow on the opposing surfaces of the sheets as films comprising an inflatable resilient and somewhat conformable tube between the sheets engaging with said the space between the sheets, and means for causing the liquid to flow on the opposing surfaces of the sheets as films comprising an inflatable resilient tube between the sheets cooperable with said surfaces.

10. In apparatus for the transfer of sensible and latent heat, a bank of horizontally spaced substantially vertical sheets, means closing the alternate spaces between the sheets at one side of the bank, means closing the other spaces at the other side of the bank, means for supplying liquid to the upper parts of the spaces to flow down the sheets, and means for circulating air through the open sides of the spaces.

11. In apparatus for the transfer of sensible and latent heat, a bank of horizontally spaced substantially vertical sheets, means closing the alternate spaces between, the sheets at one side of the bank, means closing the other spaces at the other side of the bank, means for supplying liquid to the upper parts of the spaces to flow down the sheets, substantially horizontal partitions extending into the spaces from their open sides, and means for circulating air through the open sides of the spaces.

12. In apparatus for the transfer of sensible and latent heat, a bank of horizontally spaced substantially vertical sheets, the surfaces of the sheets being grooved, and regulable means for providing films of liquid on the said surfaces comprising a manifold at a side of the bank, expansible tubes extending through the spaces between the sheets and having communication with the manifold, means for admitting fluid under pressure to the manifold to expand the tubes into sealing cooperation with said surfaces, and means for supplying liquid to the spaces above the tubes.

13. In apparatus for the transfer of sensible and latent heat, a bank of horizontally spaced substantially vertical sheets, the surfaces of the sheets being grooved, and regulable means for providing films of liquid on the said surfaces comprising a manifold at each side of the bank having spaced openings, expansible resilient tubes extending horizontally through the spaces between the sheets and having parts of lessened external diameter confined in said openings, tubular ferrules in said parts of the tubes maintaining the internal diameter of the tubes, means for supplying fluid under pressure to the manifolds to expand'the tubes against the sheets, and. means for delivering liquid to the spaces above the tubes.

vl4. In apparatus of the character described two spaced generally vertical sheets for exposing films of liquid, the opposing surfaces of the sheets being provided with grooves directed and related in size and shape to a drop of the liquid to cause small volumes of the liquid to be distributed substantially uniformly over said surfaces as self sustaining fiowing films, means for delivering the liquid to the space between the sheets, and means for causing the liquid to flow on said surfaces as films comprising an inflatable resilient tube between the sheets engaging said grooved surfaces in a plane below the liquid delivering means.

PAUL A. SCHERER- o garmrl" 

